79652c510a
objects with SF_IMMUTABLE, SF_APPEND, or SF_NOUNLINK. * Document that non-superusers cannot set or clear any SF_* flag (setting fails with EPERM, clearing is silently ignored). * Document that superusers cannot change any flag if one of SF_IMMUTABLE, SF_APPEND, SF_NOUNLINK is set and securelevel is greater than 0. * Document SF_SNAPSHOT and note that it is maintained by the system and is, for this reason, impossible to set to clear by any user. PR: docs/33877 Submitted by: harti Help by: George Marsellis <gam9478@njit.edu> MFC after: 1 week
238 lines
6.2 KiB
Groff
238 lines
6.2 KiB
Groff
.\" Copyright (c) 1989, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)chflags.2 8.3 (Berkeley) 5/2/95
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.\" $FreeBSD$
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.\"
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.Dd May 5, 2002
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.Dt CHFLAGS 2
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.Os
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.Sh NAME
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.Nm chflags ,
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.Nm lchflags ,
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.Nm fchflags
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.Nd set file flags
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/stat.h
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.In unistd.h
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.Ft int
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.Fn chflags "const char *path" "u_long flags"
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.Ft int
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.Fn lchflags "const char *path" "int flags"
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.Ft int
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.Fn fchflags "int fd" "u_long flags"
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.Sh DESCRIPTION
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The file whose name
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is given by
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.Fa path
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or referenced by the descriptor
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.Fa fd
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has its flags changed to
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.Fa flags .
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.Pp
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The
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.Fn lchflags
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system call is like
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.Fn chflags
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except in the case where the named file is a symbolic link,
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in which case
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.Fn lchflags
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will change the flags of the link itself,
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rather than the file it points to.
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.Pp
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The flags specified are formed by
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.Em or Ns 'ing
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the following values
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.Pp
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.Bl -tag -width "SF_IMMUTABLE" -compact -offset indent
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.It UF_NODUMP
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Do not dump the file.
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.It UF_IMMUTABLE
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The file may not be changed.
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.It UF_APPEND
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The file may only be appended to.
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.It UF_NOUNLINK
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The file may not be renamed or deleted.
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.It UF_OPAQUE
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The directory is opaque when viewed through a union stack.
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.It SF_ARCHIVED
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The file may be archived.
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.It SF_IMMUTABLE
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The file may not be changed.
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.It SF_APPEND
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The file may only be appended to.
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.It SF_NOUNLINK
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The file may not be renamed or deleted.
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.It SF_SNAPSHOT
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The file is a snapshot file.
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.El
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.Pp
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If one of
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.Dq SF_IMMUTABLE ,
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.Dq SF_APPEND ,
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or
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.Dq SF_NOUNLINK
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is set a non-super-user cannot change any flags and even the super-user
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can change flags only if securelevel is greater than 0.
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(See
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.Xr init 8
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for details.)
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.Pp
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The
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.Dq UF_IMMUTABLE ,
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.Dq UF_APPEND ,
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.Dq UF_NOUNLINK ,
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.Dq UF_NODUMP ,
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and
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.Dq UF_OPAQUE
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flags may be set or unset by either the owner of a file or the super-user.
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.Pp
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The
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.Dq SF_IMMUTABLE ,
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.Dq SF_APPEND ,
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.Dq SF_NOUNLINK ,
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and
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.Dq SF_ARCHIVED
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flags may only be set or unset by the super-user.
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Attempts to set these flags by non-super-users are rejected, attempts by
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non-superusers to clear flags that are already unset are silently ignored.
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These flags may be set at any time, but normally may only be unset when
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the system is in single-user mode.
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(See
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.Xr init 8
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for details.)
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.Pp
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The
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.Dq SF_SNAPSHOT
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flag is maintained by the system and cannot be changed by any user.
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.Sh RETURN VALUES
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.Rv -std
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.Sh ERRORS
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The
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.Fn chflags
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system call will fail if:
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.Bl -tag -width Er
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.It Bq Er ENOTDIR
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A component of the path prefix is not a directory.
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.It Bq Er ENAMETOOLONG
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A component of a pathname exceeded 255 characters,
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or an entire path name exceeded 1023 characters.
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.It Bq Er ENOENT
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The named file does not exist.
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.It Bq Er EACCES
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Search permission is denied for a component of the path prefix.
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.It Bq Er ELOOP
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Too many symbolic links were encountered in translating the pathname.
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.It Bq Er EPERM
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The effective user ID does not match the owner of the file and
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the effective user ID is not the super-user.
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.It Bq Er EPERM
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One of
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.Dq SF_IMMUTABLE ,
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.Dq SF_APPEND ,
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or
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.Dq SF_NOUNLINK
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is set and the user is either not the super-user or
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securelevel is greater than 0.
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.It Bq Er EPERM
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A non-super-user tries to set one of
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.Dq SF_IMMUTABLE ,
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.Dq SF_APPEND ,
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or
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.Dq SF_NOUNLINK .
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.It Bq Er EROFS
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The named file resides on a read-only file system.
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.It Bq Er EFAULT
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The
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.Fa path
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argument
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points outside the process's allocated address space.
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.It Bq Er EIO
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An
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.Tn I/O
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error occurred while reading from or writing to the file system.
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.It Bq Er EOPNOTSUPP
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The underlying file system does not support file flags.
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.El
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.Pp
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The
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.Fn fchflags
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system call will fail if:
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.Bl -tag -width Er
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.It Bq Er EBADF
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The descriptor is not valid.
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.It Bq Er EINVAL
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The
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.Fa fd
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argument
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refers to a socket, not to a file.
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.It Bq Er EPERM
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The effective user ID does not match the owner of the file and
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the effective user ID is not the super-user.
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.It Bq Er EPERM
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One of
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.Dq SF_IMMUTABLE ,
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.Dq SF_APPEND ,
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or
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.Dq SF_NOUNLINK
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is set and the user is either not the super-user or
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securelevel is greater than 0.
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.It Bq Er EPERM
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A non-super-user tries to set one of
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.Dq SF_IMMUTABLE ,
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.Dq SF_APPEND ,
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or
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.Dq SF_NOUNLINK .
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.It Bq Er EROFS
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The file resides on a read-only file system.
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.It Bq Er EIO
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An
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.Tn I/O
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error occurred while reading from or writing to the file system.
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.It Bq Er EOPNOTSUPP
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The underlying file system does not support file flags.
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.El
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.Sh SEE ALSO
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.Xr chflags 1 ,
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.Xr fflagstostr 3 ,
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.Xr strtofflags 3 ,
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.Xr init 8 ,
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.Xr mount_unionfs 8
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.Sh HISTORY
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The
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.Fn chflags
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and
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.Fn fchflags
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system calls first appeared in
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.Bx 4.4 .
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